SSL_GET_VERSION(3)         Library Functions Manual         SSL_GET_VERSION(3)

NAME
     SSL_get_version, SSL_is_dtls, SSL_version - get the protocol information
     of a connection

SYNOPSIS
     #include <openssl/ssl.h>

     const char *
     SSL_get_version(const SSL *ssl);

     int
     SSL_is_dtls(const SSL *ssl);

     int
     SSL_version(const SSL *ssl);

DESCRIPTION
     SSL_get_version() returns the name of the protocol used for the
     connection ssl.

     SSL_is_dtls() returns 1 if the connection is using DTLS, 0 if not.

     SSL_version() returns an integer constant representing that protocol.

     These functions only return reliable results after the initial handshake
     has been completed.

RETURN VALUES
     The following strings or integers can be returned by SSL_get_version()
     and SSL_version():

     "TLSv1" or TLS1_VERSION
             The connection uses the TLSv1.0 protocol.

     "TLSv1.1" or TLS1_1_VERSION
             The connection uses the TLSv1.1 protocol.

     "TLSv1.2" or TLS1_2_VERSION
             The connection uses the TLSv1.2 protocol.

     "TLSv1.3" or TLS1_3_VERSION
             The connection uses the TLSv1.3 protocol.

     "DTLSv1" or DTLS1_VERSION
             The connection uses the Datagram Transport Layer Security 1.0
             protocol.

     "DTLSv1.2" or DTLS1_2_VERSION
             The connection uses the Datagram Transport Layer Security 1.2
             protocol.

     "unknown"
             This indicates an unknown protocol version; it cannot currently
             happen with LibreSSL.

     SSL_is_dtls() returns 1 if the connection uses DTLS, 0 if not.

SEE ALSO
     ssl(3)

HISTORY
     SSL_get_version() and SSL_version() first appeared in SSLeay 0.8.0 and
     have been available since OpenBSD 2.4.

     SSL_is_dtls() first appeared in OpenSSL 1.1.0 and has been available
     since OpenBSD 6.9.

Linux 6.8.7-arch1-1             April 15, 2021             Linux 6.8.7-arch1-1